This is the 3rd most frequent Hungarian word.
is
"Is" in Hungarian means "also" or "too."
Here, 'is' means 'also' or 'too', indicating inclusion in the action expressed by the verb, aligned with the subject.
Én is szeretem a könyveket.
I also like books.
In this sentence, 'is' similarly denotes 'also', referring to the additional subject participating in the event.
Ő is ott volt a partin.
He was also at the party.
Here, 'is' appears to add inclusion to the noun subject, signifying that this subject shares the same action as others potentially described in the context.